Prescription medication (drug) treatments for depression are thought to work by increasing the amount
of neurotransmitters in the brain.
Communication between nerve cells in the central nervous system is an electrochemical process, and
neurotranmitters are the chemicals which enable one nerve cell to 'talk' to the next one and to send
messages on through the whole nervous system, and specifically the brain.
The neurotransmitters that seem to be of greatest relevance in depression are norepinephrine and serotonin.
Prescription medications always have a common name and a trade name.
For example the drug Doxepin is sold under the name Deptran or Sinequan.
Antidepressant medications usually need to be taken as prescribed for 4 to 6 weeks before you can expect to notice significant improvements in mood. The World Health Organisation recommends that treatment (medication) continues for at least six months after the ceasation od symptoms, this is to reduce the chance of the depression returning.
Finding the right antidepressant and the right dosage is likely to involve a period of trial and adjustment, and you will need to work with your doctor on this.
It is very important that you are open and honest with your doctor about your medication and any concerns you have so that they can help you find the right one and the right dosage for you.
We are all different, and unfortunately there is no simple set of rules!
Research:
'New' and 'Old' Antidepressants: All Equal in the Eyes of the Lore?
British Journal of Psychiatry, 179, 95-96.
Gordon Parker - Professor of Psychiatry, Mood Disorders Unit, Prince Of Wales Hospital, Sydney.
There are five categories of antidepressant medications that work in different ways:
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Tricyclic antidepressants (TCAs)
These drugs, of which Imipramine (Tofranil) was the
first to be used, were developed in the sixties. Other drugs in this class are
Amitriptyline ( Elavil) and (Endep),
Nortriptyline (Aventyl), Bupropion (Zyban),
Desipramine (Norpramin), Trazodone (Desyrel),
Doxepin (Sinequan), Amoxapine (Asendin), Dothiepin
(Dothep) and (Prothiaden),
and Clomipramine (Anafranil).
Tricyclics were seen as part of the "drug revolution" in psychiatry,
but numerous different drugs have been developed since they came on the market.
While tricyclics do have significant side-effects - which include constipation,
difficulty urinating, feeling faint while standing, sleepiness, and confusion - they are
not addictive (in fact, none of the anti-depressants are addictive in the way that, say,
Valium is addictive).
Tricyclics are dangerous if taken in overdose because they can affect heart rhythm.
Their anti-depressant effect is thought to be due to the fact that they bind to neurotransmitter receptor
sites on the surface of nerve cells, thereby blocking the neurotransmitters and increasing their local concentration.
Neurotransmitters that are affected are norepinephrine, dopamine, and serotonin.
Side-effects:
Dry mouth, drowsiness, sweating, blurred vision, constipation, and difficulty passing urine.
Research:
The place for the tricyclic antidepressants
in the treatment of depression. An abstract.
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Monoamine oxidase inhibitors (MAOIs)
This class of drugs inhibits the action of monoamine oxidase whose function is to
degrade excessive levels of norepinephrine and serotonin.
The drug slows down this degrading action meaning that more norepinephrine and serotonin
are available.
The drug Iproniazid was first used for tuberculosis and it was observed that it
increased patients' well-being. Although this drug has now been withdrawn, several
others in the same class are used for depression, although not usually as the first
choice treatment.
MAOI's can lower blood pressure and cause headaches, dizziness, and fainting.
It is important to avoid some foods such as cheese and red wine while taking MAOI's.
Be sure to check this out with your doctor.
Examples are Phenelzine (Nardil) and Tranylcypromine (Parnate).
Side effects: Insomnia is the most common adverse reaction.
Other common side-effects include dizziness, dry mouth, lightheadedness, an excessive fall in
blood pressure when standing, constipation, and weakness.
Less common side-effects are: a rash, nausea and vomiting and headaches.
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Selective serotonin-reuptake inhibitors (SSRIs)
This is a newer group of drugs of which Fluoxetine (Prozac,
Lovan)
is probably the most well-known.
Others are Fluvoxamine (Luvox), Citalopram
(Cipramil), Paroxetine (Paxil) and (
Aropax ), and Sertraline (Zoloft).
These drugs are more selective in their actions (hence the name) and should therefore have fewer side-effects
than the MAOIs and Tricyclics. However, many will experience nausea, insomnia and anxiety.
Loss of sexual function is a further side-effect which is not often spoken about in relation to the SSRI's.
Since the late 1980's billions of dollars have been poured into researching newer and better versions of these drugs.
SSRI's compete with serotonin to be taken up by the nerve cells, thus leaving more serotonin available outside the cell.
The different drugs vary in their potency to affect uptake, but this does not seem to relate to their ability to alleviate
depression. Sometimes, several different brand names will need to be tried before one that is suitable for
a particular individual can be found.
Side effects:
Dry mouth, drowsiness, sweating, blurred vision, constipation, difficulty passing urine.
If you experience unusual bruising or bleeding you should also consult your doctor as soon as possible.
This is quite a rare side effect, but good to be aware of it in case.
Research:
Abstract of an analysis that compares 5 SSRIs.
Risks and benefits of selective serotonin reuptake
inhibitors in the treatment of depression
SSRIs in the treatment of
obsessive-compulsive disorder
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Medications for Bipolar Disorder
Lithium carbonate is commonly used for bipolar disorder.
Interestingly, it was an Australian psychiatrist John Cade who did early studies on lithium - he used
guinea pigs (real ones) - and found that it had a tranquillising effect.
Its mechanism of action is not understood, but it is presumed to affect the regulation of neurotransmitters.
Side effects include thirst, reduction in thyroid function, and a fine tremor in the hands.
Sometimes, lithium is prescribed in addition to a TCA to augment its effects.
Other drugs used for bipolar disorder include the antiepileptics Carbamazepine and Valproate.
Side-effects:
Lithium is relatively toxic and can affect kidney function. Side effects include tremor, thirst and weight gain.
Research:
The prevalent clinical spectrum
of bipolar disorders: beyond DSM-IV
Anti-bipolar therapy:
mechanism of action of lithium
Pharmacotherapy in bipolar disorder
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Newer-style antidepressants
There are several drugs which don't fall into a group or class and have their own mode of action,
but few are readily available in Australia for depression.
Medications in this category include bupropion hydrochloride
(Wellbutrin/Zyban), Mirtazapine (Avanza),
Desyrel (Trazodone),
Serzone (Serzone), and Venlafaxine (Efexor).
They are in their own category because they have a different chemical action, and different side effects.
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The factual information above was compiled from:
Dr. Catherine Delin 
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